A question about fixing

[Oxalis80]

May I ask you a question about fixing?

I'm interested in making semi-permanent slides with botanical specimens (sections, peelings); I'm thinking to use 30% vinegar + 70% alcohol 96°, because it's easy, non toxic and should balance the shrinking effect of alcohol (I don't need professional results).

The question is, how long should I fix? Minutes (5m, 10m) or hours (24h, overnight?)? I didn't understand the "order of magnitude" of that process for thin botanical specimens. (Maybe I read too much and made too little practice. .)

Thank you again!

PS: at the supermarket I found a "chemical" vinegar obtained from alcohol instead of wine. The smell is really "acetic" (like acetic silicone sealant), if compared with the aromatic scent of a good quality wine vinegar, but for household and microscopy it's perfect (no deposit at all, only a light staining to simulate the color of real winegar).

[mrsonchus]

Hi, fix truly tiny tissue (I've botanical experience only I'm afraid) such as several single anthers for about 2hrs - anything larger (keep the max dimension below about 5mm) for >= 24hrs and you won't go far wrong.
The total acetic-acid (from your vinegar) should be about 5% (of the mixed-fixative) as this gives a good balance to the shrinking effect of the OH. The acetic acid causes fixing cells to 'swell' - whilst the OH causes them to 'shrivel' - the counterbalance will see them fixed just right when perfected.

70% OH can be good too but must be approached via an increasingly strong series, say 10mins in 20%, then 20%....right up to 70% then left for >= 24 hrs to complete fixation. Then the tissue will be fine in the 70% OH for years.

Good luck, let us know how you get on....